The purpose of this study is assess Sativex as a treatment for Cannabis dependence. Initially a pilot study will be conducted in five subjects seeking treatment for cannabis dependence to ensure that our planned self-titration regimen is appropriate using Sativex. This phase will be open label, with no placebo control. Then, there will be a twelve-week, double-blind, placebo-controlled study in male and female subjects seeking treatment for cannabis dependence (n=40). All participants will receive a combination of pharmacotherapy (Sativex Spray or Placebo Spray) associated with a weekly intervention of combined Motivational Enhancement Therapy and Cognitive Behavioral Therapy (MET/CBT). The subjects will have to come daily to the centre to assess usage of medication. Following the medication phase, participants will have a follow-up weekly for another four weeks and then monthly until the 6 month follow up visit after the target quit date. The investigators are planning to enroll 45 subjects over the two-year period.